Apparatus for stitching vehicle interior components

ABSTRACT

An apparatus for stitching an interior component is disclosed herein. The component having an outer skin layer and the apparatus is a single needle chain stitch machine with a rotary looper and wherein a needle of the apparatus descends through the interior component and a hook of the rotary looper engages a thread loop formed during retraction of the needle after it has descended through the interior component; and wherein the apparatus further includes a mechanism for moving the interior component relative to the needle and looper to establish a stitch length.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 61/505,836, filed Jul. 8, 2011, the contents of which areincorporated herein by reference thereto.

BACKGROUND

This invention relates to an interior structure for a vehicle interior.More particularly, the invention relates to an apparatus for stitchingvehicle interior components.

Currently, most stitching found in an automotive interior is of thefunctional variety, wherein two or more pieces of material (leather,vinyl, TPO, cloth, etc) are cut from a pattern and sewn together(cut-n-sew) prior to being wrapped around a component such as a seatcushion, head rest, arm rest, console lid, instrument panel substrate,etc. Such functional stitching is very labor intensive and is normallyused only where required on low and mid-class vehicles. Functionalstitching on decorate components such as instrument panel retainers anddoor panels has typically been restricted to higher class vehicles dueto cost.

In recent years, automotive original equipment manufacturers (OEMs) haveshown an interest in applying the “stitched” look to more vehicles overa wider range of price classes. A simulated non-functional stitch hasbeen used in some applications; however, the ability to offer asimulated stitch in a contrasting color is not production feasible atthis time. Additionally, more OEMs are requested that a real or “live”stitch be used on decorate components to provide the look and feel of atrue cut-n-sew component.

Accordingly, it is desirable to provide a live, non-functional stitch ondecorative automotive trim components.

SUMMARY OF THE INVENTION

An apparatus for stitching an interior component, having an outer skinlayer, wherein the apparatus is a single needle chain stitch machinewith a rotary looper and wherein a needle of the apparatus descendsthrough the interior component and a hook of the rotary looper engages athread loop formed during retraction of the needle after it hasdescended through the interior component; and wherein the apparatusfurther comprises a mechanism for moving the interior component relativeto the needle and looper to establish a stitch length.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features, advantages and details appear, by way of example only,in the following description of embodiments, the description referringto the drawings in which:

FIG. 1 is a schematic illustration of an apparatus for stitching acomponent of a vehicle;

FIG. 2 sequentially illustrates a stitching sequence of an exemplaryapparatus of the present invention;

FIG. 3 is cross sectional view of a component stitched in accordancewith an exemplary embodiment of the present invention;

FIG. 4 is a schematic illustration of an apparatus for stitching acomponent of a vehicle according to an alternative exemplary embodiment;and

FIG. 5 is a schematic illustration of an apparatus for stitching acomponent of a vehicle according to yet another alternative exemplaryembodiment.

DETAILED DESCRIPTION

Turning now to the drawings, wherein to the extent possible likereference numerals are utilized to designate like components throughoutthe various views, an interior portion of a vehicle is illustrated. Inone implementation interior portion is a portion of an instrument panelof a vehicle. Also illustrated, is an apparatus for stitching theinterior portion.

The interior portion may be a single layer or multi-layeredconstruction. In one embodiment, the interior portion includes at leastan outer skin layer having a substantially smooth outer surface and anunderside facing away from the outer surface. The outer skin layer ispreferably formed of a plastic material of substantial flexibility andaesthetically pleasing character. In one embodiment, the interiorportion is a decorative element of a vehicle interior.

In order to enhance the softness of interior portion and in oneembodiment, a layer of cushioning support material may be provided inthe region below the outer skin layer. It is contemplated that thecushioning support material may be of any number of differentconstructions although a foamed material such as cross linkedpolypropylene (XLPP) foam may be potentially preferred. A substratepanel of dimensionally stable plastic or other suitable material canalso be disposed below the cushioning support material.

According to one potentially preferred embodiment, the cushioningsupport material and the substrate panel serve cooperatively to providea support structure for the outer skin layer.

It is contemplated that XLPP foam forming the cushioning supportmaterial may be blown between the outer skin layer and the substratepanel so as to form a multi-layered composite structure. It is alsocontemplated that the cushioning material may be attached to the outerskin layer in a preliminary cladding operation so as to form apreliminary layered composite which may thereafter be applied across anysubstrate panel as may be utilized.

Still further, the interior piece or decorative element may be anyone ofa single layer (skin only), a double layer (skin/foam) or a triple layer(skin/foam/substrate). Accordingly, the apparatus disclosed herein incontemplated as being used with anyone of the aforementioned interiorpiece configurations.

As discussed above, there is a desire to provide a live, non-functionalstitch on decorative automotive trim components without using costlycut-n-sew technologies. Typically, live non-functional stitching can beapplied in one of the following ways:

I. Stitch a pattern on an unformed single or multilayer construction oftrim material and wrap the sewn trim sheet around a preformed/precutsubstrate;

II. Stitch a pattern on a preformed single or multilayer construction oftrim material and bond the sewn trim preform to a preformed moldedsubstrate; and

III. Stitch a pattern on a flat or relatively flat single or multilayertrim & substrate component construction.

As the part complexity increases, in addition to the desire of many OEMsto place the live, nonfunctional stitching along the edge and othertight confines of the component, the ability to access these areas withconventional sewing equipment becomes increasingly difficult. Speciallong arm, high post stationary sewing machines with custom postextensions have been designed and are being used with some success tostitch in these confined areas. However, as part size increases, itbecomes increasingly difficult for the sewing machine operator tomanipulate the part/preform under the sewing head without eitherdamaging the part or producing an irregular stitch length or misalignedstitch.

As a result, movement of the sewing machine around a fixed part becomesa more plausible solution as the part and stitch complexity increases.Movement is commonly guided by a 6 axis robot in order to provide accessto all areas of the part. In addition to provide the ability to sew alarge 3D component without damaging the part, the robot minimizesconcerns regarding irregular stitch length and stitch misalignment.

Several types of sewing heads have been developed for attachment to arobot. Both post bed type and cylinder type robotic stitching heads havebeen developed for sewing 3D components. Both chain and lock type stitchpatterns have also been utilized. Cylinder type machines designed todate have either been chain stitch with a hook looper in the cylinderarm or a lock stitch with a bobbin oriented with its axis of rotation ina horizontal fashion. Post bed type machines have also consisted of achain stitch hook looper located at the top of the post or a lock stitchwith a bobbin oriented vertically or horizontally at the top of thepost.

The instant application is directed to an improvement in the existingrobotic sewing head design technology to enable increased access toconfined stitch areas.

Exemplary embodiments of the invention described herein, consists of arobotic sewing/stitching head design that enhances the ability to stitchin confined areas of a three-dimensionally shaped part. The designutilizes a chain type stitch with the use of a rotary looper at the endof a combination post and cylinder bed (see at least FIG. 1).

In FIG. 1, a lower shaft 1 is also driven by the same servo motor 10(via mechanical linkage 17) that drives an upper shaft 2 and needle barassembly 2 a. Shaft 1 is configured to drive a series of secondary lowershafts (3 and 4) through appropriate gearings 5 and bearing supports 6.

A rotary looper 7 is attached to the output of the last shaft 4 which inturn rotates to hook and secure the top thread to the underside of acomponent 8 being sewn. The position and dimensions of the lower armassembly 9 is such that all areas of the component 8 being sewn can beaccessed. It is desirable to size the diameter of the rotary looper andassociated lower arm enclosure to maximize access to the backside of thepart while providing the ability to accommodate the desired thread sizeand stitch length. For example, the configuration of the rotary looper 7allows an underside area 38 of component 8 to be accessed. This wouldnot be feasible with a vertically driven mechanism located directlybelow the rotary looper 7. An extension 39 of the appropriatelyconfigured diameter 41 of the rotary looper is shown in FIG. 1.

The means of driving the rotary looper is not limited to the descriptionabove and can be reconfigured accordingly to achieve the same effect,namely access into confined area such as area 38.

A typical operation sequence for a single needle chain stitch machinewith a rotary looper and single thread is described below and is thepreferred, but not only, method of stitching to accomplish a compactstitching head construction. As shown in FIG. 2, the stitching sequencebegins with the needle 11 descending through a material 12 and passingthrough the thread loop 13 generated during the previous cycle. A newthread loop 14 is generated via the friction between the thread andmaterial as the needle 11 retracts through the material. The hook 15 ofthe rotary looper 16 engages the new thread loop during needleretraction. After the needle exits the material, the material movesrelative to the needle and looper to establish the stitch length via amechanism that is configured to move the material. The aforementionedmechanism is illustrated schematically via box 19 in FIGS. 1, 4 and 5.Box 19 may represent a mechanism for moving the part or component 8relative to the sewing head 21 or alternatively a robot (as mentionedabove) coupled to the sewing head 21 and configured to move the sewinghead 21 relative to a stationary part or component 8. Still further andin yet another embodiment, a pair of mechanisms 19 (e.g., one robot andone for moving the part) may operate in concert with each other tosimultaneously move the part 8 and the sewing head 21 or alternativelythe two mechanisms 19 may alternate in their operation (e.g., partmovement then sewing head movement). The material of component 8movement can be accomplished via a feed dog mechanism and walking footintegral to a stationary sewing head 21 or the sewing head 21 can bemoved relate to a fixed material position by for example a robot. Duringthe advancement of the material relative to the sewing head 21 via themechanism 19 the rotary looper releases the previous thread loop fromthe looper and the thread is drawn tightly against the bottom of thematerial. The looper hook continues to rotate and position itself toengage the next loop once again as the needle creates a new piercing andmoves through the bottom of its stroke. This sequence continued untilthe stitching pattern is completed.

The completed stitch pattern 23 appears as shown in FIG. 3. Preformedmaterials used with this stitching head design are typically, but notlimited to, thermoplastic vacuum formed or slush cast formed sheet orvacuum formed thermoplastic sheet of multilayer construction consistingof, at minimum, a skin 25 and foam layer 27 but also may include abarrier layer behind the foam as well as a rigid thermoplastic polymerthat serves as the substrate 29 for the three dimensionally formed part.

An alternative exemplary design utilizes a chain type stitch with theuse of an offset looper arm (see FIG. 4) or an offset looper hook (seeFIG. 5) at the end of a combination post and cylinder bed in lieu of arotary looper hook. The use of a looper arm/hook configuration enablesthe use of both a top thread 31 and a bottom thread 33 (illustratedschematically) to further enhance the security of the stitch against thesewn part.

In the case of the offset looper arm (FIG. 4), the lower shaft 1 issupported by bearings 30 and the lower shaft 1 is also driven by thesame servo motor 10 that drives the upper shaft 2 and needle barassembly 2 a via mechanical linkage 17. The lower shaft is alsoconfigured to direct drive an offset looper arm 32 such that the desiredrotational movement of the arm 32 and hook 34 is achieved. The offset ofthe looper arm 32 is illustrated as length 33 and the looper armhouses/contains a looper hook 34 that engages the loops formed by theneedle 36 in a fashion similar to that described in FIG. 2. The positionand dimensions of the lower arm assembly 9 is such that all areas of thecomponent 12 being sewn can be accessed. It is desirable to design thedepth of the offset 33 on the looper arm 32 and associated lower armenclosure to maximize access to the backside of the part 12 whileproviding the ability to accommodate the desired thread size and stitchlength.

In the case of the offset looper hook 34 (FIG. 5), the same machineconfiguration exists as with the offset looper arm 32 with the exceptionthat the hook 34 instead of the arm 32 contains the offset 33 requiredto gain access to the restricted areas of the part.

Accordingly, an underside of the part 12 in area 38 can be access viathe offset 33.

While the invention has been described with reference to an exemplaryembodiment, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the inventionwill include all embodiments falling within the scope of the presentapplication.

What is claimed is:
 1. In combination, an apparatus for stitching aninterior trim piece of a vehicle and the interior trim piece, whereinthe interior trim piece comprises an outer skin layer, and wherein theapparatus is a single needle chain stitch machine with a rotary looperwherein the rotary looper extends from a portion of the apparatus suchthat a portion of the interior trim piece being stitched is locatedabove and below the rotary looper as the rotary looper rotates andwherein a needle of the apparatus descends through the interior trimpiece and a hook of the rotary looper engages a thread loop formedduring retraction of the needle after it has descended through theinterior trim piece; and wherein the apparatus further comprises amechanism for moving the interior trim piece relative to the needle andlooper to establish a stitch length.
 2. The combination as in claim 1,wherein the rotary looper releases a previous thread loop as theinterior trim piece is moved by the mechanism and wherein the threadloop is drawn tightly against a bottom of the interior trim piece. 3.The combination as in claim 1, wherein the outer skin layer is formedfrom the group consisting of vinyl, leather and thermoplasticpolyolefin; and wherein an intermediary layer foam layer is applied tothe outer skin layer.
 4. The combination as in claim 3, wherein aplastic substrate layer is applied to the foam.
 5. The combination as inclaim 1, wherein the portion of the interior trim piece located aboveand below the rotary looper also extends around at least one verticallength or diameter of the rotary looper.
 6. The combination as in claim5, wherein the interior trim piece is a portion of an instrument panelof the vehicle.
 7. The combination as in claim 2, wherein the outer skinlayer, is formed from the group consisting of vinyl, leather andthermoplastic polyolefin; and an intermediary foam layer is applied tothe outer skin layer.
 8. The combination as in claim 7, wherein aplastic substrate layer is applied to the foam.
 9. The combination as inclaim 8, wherein the interior trim piece is a portion of an instrumentpanel of the vehicle.
 10. In combination, an apparatus for stitching aninterior trim piece of a vehicle and the interior trim piece, theinterior trim piece comprising an outer layer, and wherein the apparatushas a rotatable looper arm extending therefrom, the rotatable looper armbeing rotatably driven by a shaft and having a hook portion extendedfrom the looper arm via an extension such that the hook portion of thelooper arm can be inserted into an area of the interior trim piecehaving a portion of the interior trim piece located above and below thehook portion as it is rotatably driven by the shaft.
 11. The combinationas in claim 10, wherein the rotatable looper arm is directly driven alower shaft coupled to a motor and the motor drives an upper shaft thatdrives a needle for stitching the interior trim piece.
 12. Thecombination as in claim 11, wherein the extension of the rotatablelooper arm is parallel to the lower shaft.
 13. The combination as inclaim 12, wherein the interior trim piece is a portion of an instrumentpanel.
 14. In combination, an apparatus for stitching an interior trimpiece of a vehicle and the interior trim piece, the interior trim piececomprising an outer layer and wherein the apparatus has a rotatable armmember and a hook extending from the arm member, the arm member beingrotatably driven by a shaft and the hook extends outwardly away from thearm such that the hook can be inserted into an area of the interior trimpiece such that a portion of the interior trim piece is located aboveand below the hook as it is rotatably driven by the shaft.
 15. Thecombination as in claim 14, wherein the arm member of the rotary looperis directly driven by the shaft and the shaft is coupled to a motor andthe motor drives an upper shaft that drives a needle for stitching theinterior trim piece.
 16. The combination as in claim 15, wherein theinterior trim piece is a portion of an instrument panel of the vehicle.17. The combination as in claim 1, wherein the mechanism is configuredto directly move the interior trim piece with respect to the needle andthe rotary looper.
 18. The combination as in claim 1, wherein themechanism is configured to directly move the needle and the rotarylooper relative to the interior trim piece.